Landing-gear for aircraft.



I(mi. CURIISS.

LANDING GEAR FOR AIRCRAFT.

APPLICATION FILED APIILZIl I9I7.

1 ,246,020. Patented Nov; 6, 1917.

2 SHEETS-SHEET I.

GLENN HCL/s251255 i @Mor/mud G. H. CURTISS.

LANDING GEAR 'FOR AIRCRAFT.

APPLICAIION man Ayn. 27. 1911.

1,246,020. Patented Nov. 6, 1917.

2 SHEETS-SHEET 2.

GELE-NN H .Cumvss UNITEB STATES PATENT FFE.

GLENN H. CURTISS, 0F BUFFALO, NEW YORK, ASSIGNOR T0 CURTISS AEROPLANEAND MOTOR CORPORATION, A CORPORATION 0F NEW YORK.

LANDING-GEAR FOR AIRCRAFT.

Specification of Letters Patent.

Patented Nov. 6, 1917.

Original application led J'i'ily 14, 1915, Serial No. 39,836. Dividedand this application iiled April 27, 1917. Serial N o. 164,904.

To all whom t may concern.'

Be it known that I, GLENN H. Cun'rrss, a citizen of the United States,residing at Buffalo, in the county of Erie and State of New York, haveinvented certain new and useful Improvements in Landing-Gear forAircraft, of which the following is a specification.

My invention relates to landing gear for aircraft. The characteristic ofthe invention is set forth in an application iiled July 14, 1915, SerialN o. 39,836, of which thepresent application is a division. Theprincipal object of the invention is the production of a landing earthrough the use of which landing may e made upon broken or extremelyrough ground without damage to the machine or discomfort to the flyingcrew.

A landing gear in order to attain this object must necessarily loe ofvery sturdy construction. This very fact has heretofore been a drawback,inconsistent as it may seem, for the reason that when the structure ismade sufficiently strong to stand up under the severe strains imposedupon it, the proper articulation and yielding connection of the variousparts for the introduction of equalizing connections between the wheelsbecomes more diiiicult. By my invention 1 have obtained this latter-endwithout any sacrifice whatsoever in strength and sturdiness. Moreover,resistance during flight through the air is minimized' and the landinggear adapted to the larger and heavier types of aircraft whereinmultiple motors are provided.

In its broad aspect the inventionis characterized by a relatively broadwheel base. T he landing gear wheels are arranged, two at each side ofthe longitudinal axis of the machine, with the wheels at opposite sidesin tandem. Equalizing connections common to the wheels in airs togetherwith articulated connections w ich extend out laterally from the body ofthe craft constitute the preferred wheel mounting. pairs, referablyunderlie the motors.

OI' t e drawings, wherein like characters of reference designates likeor corresponding parts:

Figure 1 is a side elevation of a twin motored aeroplane equipped withthe landing gear of my invention;

The wheels, in i 'that portion of the landing gear in the immediatevicinity thereof;

Fig. 5 is a vertical sectional view of that portion of the landing gearillustrated in ig. 4, and

t. Fig. 6 is a front elevation of the modificaion. f

In the embodiment of the invention selected for illustration, 10designates the nacelle .body of the craft, 11-11 the twin motors and12-12 the supporting surfaces; the craft being of the twin screw tractortype with its power units arranged symmetrically at opposite sides ofthe fore and aft axis and in a horizontal plane above that of thenacelle. I

Axle members 13 extend out laterally in tandem pairs from the sides ofthe nacelle 10. These axlemembers are hinged at their inner ends asindicated at 14 to the nacelle body whereby their outer ends may partakeof movement in vertical planes. A Tandem or following wheels 15 aremounted in pairs on the outer ends of the axles, the wheels atl eachSide of the nacelle being herein referred to as the wheels constitutingthe respective pairs.

An equalizing member 16 interconnects the tandem wheels. The form ofthis meinber is best illustrated in Figs. 3 and 4. As shown it is aiexible laminated bow spring whereby the equalizing connection becomesalso a yielding connection. The laminations are preferably of varyinglength, the base lamination being longest and the top laminationshortest. Said base lamination is terminally rolled-in as indicated at17 to embrace respectively the axle members 13 which support the wheels15, the axle members in each instance underlying approximately the outerend of the lamination next above the `base .lamination of the spring.The top lamination of the spring is symmetrically arched as at 18 atpoints at opposite sides of its center and equidistant respectively fromits ends. These arched portions bear directly against a bearing plate 19carried at the extremity of a pillar support 2O nacelle.

dependent from the lower supporting plane 12. Said pillar supporttogether witha diagonal extending brace 21 provides in effect asubstantially V-strut, by many considered the best type of landing gearstrut yet evolved. The bearing plate or fitting 19 is equipped withopposed down-turned ears 22 and the top lamination of the bow springwith opposed upturned ears 23. Said ears are substantially complemental(see Fig. 5)

and with a pivot pin 24 provide the pivotal y support for the tandemwheels. The pivot axis, in each instance, lies intermediate the ends ofthe bow springs 16 and directly beneath the pillar strut 20.Furthermore, the lower end of each pillar strut is convexed (the fitting19 being complemental) and bears against the arched portions 18 .and itsassociated'bow spring 16. The location of the pillar supports is suchthat the thrust of the landing gear is transmitted directlyfto the mainstructure of the machine. Preferably, the pillar supports 20 are joinedat their upper ends to the front main beam (not shown) of the lowersupporting surface, while the upper ends of the diagonal braces 21 arejoined to the rear beam thereof. ln the vertical plane of the pillarsupports the motors or power units 11 are arranged, hence the weightmasses of the respective motors are thus borne directly by the tandemwheels, the wheels, as shown, approximately underlying the power units.Strong cross wiring 25 is provided between the pillar supports 20 andthe sides of the In operation asl the machine is started from the groundinto the air or alights upon the ground from the air, the tandem wheelstake up directly the impact of landing, the heavy masses of the drivingmotors being directly imposed upon them, the body structure being midwaybetween the pairs on opposite sides of the machine. rll`he equalizingconnections or bow springs 16 between the wheels equalize the load uponthe individual wheels of the pairs, each wheel moving with its axle andthe pairs together havin oscillatory movement about the points o rockingor pivotal connection with the pillar supports 20 (see 24) as they passover small or large obstructions. By virtue of this connection themachine is of an extremely easy riding nature on landing but of far morevalue than that is the freedom of shocks to vital parts and the extremesturdiness of the gear itself. Because the wheels are following ortandem they present a minimum head resistance per pair. rlhe archedportions 18 of the top lamination of the bow spring 16 prevent contactof the spring proper with the fitting 19. Otherwise, equalizing motioncould not be produced. The articulated connections are such that thelanding gear parts act independently, the one part acting principally asa support for one motor unit and the other part principally as a supportfor the other.

In Fig. 6 I have disclosed a modified form of landing gear which differsfrom the form of Figs. 1-5 inclusive principally in that the axlemembers 30 are carried to a point near the central plane of the nacelleand pivoted as at 31 to an outward extension therefrom instead of to thebottomoutside edges. In the preferred type of landing gear the axlemembers 13 are bent intermediate their ends \while in a modified type oflanding gear the axle members are straight .or unbent throughout. lnother respects the landing gear devices are identical.

Although l have described more or less precise forms and details ofconstruction, I do not intend to be understood as limiting myselfthereto as l contemplate changes in form, the proportion of parts andthe substitution of equivalents as circumstances may suggest or renderexpedient and without departing from the spirity of the invention asclaimed.

What is claimed is:

1. 1n an aeroplane, in combination, main supporting surfaces, motorunits disposed symmetrically at opposite sides of the fore and aft axisof the craft, a centrally located body, tandem wheels arrangedsymmetrically beneath said surfaces constituting a running gear, thetandem wheels at opposite sides of said4 axis directly underlying therespective motor units, and articulated connections between the tandemWheels and said central body.

2. In an aeroplane, in combination, main supporting surfaces, motorunits disposed symmetrically at opposite sides of the fore and aft axisof the craft, a centrally located body, tandem wheels arrangedsymmetrically beneathsaid surfaces constituting a running gear, thetandem wheels at opposite sides o said axis approximately underlying therespective motor units, and equalizing connections between therespective tandemwheels.

3. ln an aeroplane, in combination, main supporting surfaces, pairs oftandem wheels symmetrically disposed at opposite sides of the fore andaft axis of the craft, separate strut supports for the respective pairsof wheels, rigid connections between said strut supports and thesupporting surfaces, a centrally located body, and articulatedconnections between said wheels and said kcentral body. f

4. lln an aeroplane, in combination, main supporting surfaces, pairs oftandem wheels symmetrically disposed at opposite sides of the fore andaft axis of the craft, V-struts secured to the supporting surfaces forthe individual support of the respective pairs of wheels, and anequalizing member secured to each V-strut for equalizing the load uponthe Wheels of the tandem pairs.

5. In an aeroplane, in combination, motor units arranged symmetricallyat opposite sides of thelongitudinal axis of the-craft, supportingsurfaces, a nacelle body, outrigged axles carrying Wheels spaced fromthe sides of said nacelle body and in vertical alinement with therespective motors, and shock absorbing means intermediate the axles andthe supporting surfaces abovethem.

6. In a landing gear for aircraft, tandem Wheels arranged in pairs atopposite sides of the craft, pivoted axle members individuallysupporting the respective Wheels, equalizing members connecting the axlemembers in pairs, and separate supports for the respective equalizingmembers.

7. In a landing gear for aircraft, separate V-strut supports, anequalizing member mounted at the foot of each support, outrgged axlemembers terminally supported by said equalizing members, Wheels mountedupon said axle members, and means spacing the equalizing members fromthe supports.

8. In a landing gear for aircraft, tandem Wheels arranged in pairs atopposite sides of the craft, outrigged axle members individuallysupporting the respective Wheels, equalizing members terminallyinterconnecting the outrigged axles, means rigidly supporting theequalizing members from above, and means conjointly functioning as anelement of the equalizing member and as a means for spacing said memberfrom its rigid support.

In testimony whereof I hereunto aiix' my signature.

' cLENN H. CURTISS.

